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Published March 2019 | public
Journal Article

Fog geoengineering to abate local ozone pollution at ground level by enhancing air moisture

Yu, Shaocai ORCID icon


High concentrations of ozone (O_3) at ground level in urban and industrial regions worldwide have long been a major air pollution issue, notably during daytime because sunlights induce the photochemical production of ozone. After a review of actual techniques to clean O_3 pollution in urban and industrial regions, I present a fog geoengineering scheme for abating ozone pollution at ground level by enhancing ambient moisture locally through spraying water mist into the atmosphere. This scheme is based on my results showing that ozone levels decrease with air relative humidity. For instance, the mean O_3 concentrations decrease from 70.0 to 21.2 ppbv when relative humidity increases from below 40% to more than 80%, in Hangzhou city at midday times (11:00–16:00) without precipitation, during the "ozone season" from May to October of 2017. The mechanism of fog geoengineering is that atmosphere moisture inhibits O_3 formation by lowering air temperature, decreasing the chain length of peroxy radical chemical amplifiers (HO_2, RO_2, and RC(O)O_2), and decreasing the chain length of NO_2 by enhancing particle water, and destroys the existing O3 photo-chemically by water vapor through catalytic O_3 destruction cycle. Ozone mitigation by fog geoengineering has several advantages such as being a nature-like process, quick response, technological feasibility, efficacy, relatively low cost, and cooling effects. The proposed fog geoengineering to decrease the local O_3 at ground level could potentially be on avenue for addressing heavy O_3 pollution during the hot summer in megacities globally as expected.

Additional Information

© 2018 Springer Nature Switzerland AG. Received: 19 August 2018; Accepted: 3 September 2018; First Online: 20 September 2018. I would like to appreciate Prof. John H. Seinfeld for his very constructive, detailed, and helpful comments, the incorporation of which has led to a substantially improved manuscript. I would like to thank Dr. Eric Lichtfouse for his professional editorial comments, his suggestions for using "fog geoengineering" instead of "water spray geoengineering" and allowing using the video of natural fog on the Huangshan Mountain taken by him used in this paper. This work was partially supported by the Department of Science and Technology of China (No. 2016YFC0202702; No. 2014BAC22B06) and National Natural Science Foundation of China (No. 21577126). This work was also supported by the Joint NSFC–ISF Research Program (No. 41561144004), jointly funded by the National Natural Science Foundation of China and the Israel Science Foundation. Part of this work was also supported by the "Zhejiang 1000 Talent Plan" and Research Center for Air Pollution and Health in Zhejiang University. We also thank Yibo Zhang for help in preparation of references and Chun Xion for his help in observational data collection.

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